Solar power is the conversion of sunlight into electricity and is becoming increasingly popular as a renewable source of energy. Large-scale solar power installations are often composed of thousands of photovoltaic cells (also called solar cells) spread over large tracts of land. One major problem facing large-scale solar power installations is the accumulation of dust over photovoltaic cells, thereby decreasing the ability of the cells to receive sunlight and convert the sunlight into power. According to some published data, a dust layer of one-seventh of an ounce per square yard decreases solar power conversion by 40 percent. Dust layer deposition rates are even higher in the Middle East and other desert areas where large scale solar power installations are typically located. In this respect, a self-cleaning mechanism for the surface of solar cells would both increase the efficiency and reduce the cost of maintenance for solar installations.
Photovoltaic cells are often organized into modules, electrically connected, and mounted on a supporting structure called a photovoltaic panel or solar panel. Based on the size and quantity of solar panels in a large-scale solar panel installation, it can be a difficult and time consuming process to clean each panel. Many prior photovoltaic panel cleaning methods and systems have been created, a number of which required the use of water to clean the photovoltaic panels. This approach is impractical for photovoltaic panels installed in the Middle East and other desert areas where rain is infrequent because water may be costly, may evaporate quickly, and outdoor usage may be highly regulated by local authorities. In some instances hydrophobic films have been suggested to simplify the removal of dust during precipitation but with low levels of precipitation these films are ineffective.
Other systems involve the induction of strong electromagnetic or electrostatic fields through electrically sensitive material deposited on glass to repel dust particles that have settled on the photovoltaic panels. The presence and use of strong electrostatic fields near sensitive photovoltaic cells that may be charged poses a high risk of electrostatic discharge as well as the risk of electrocution for nearby people and animals. Also, addition of any extra layer of materials, even if transparent, can negatively affect light transmission from the sun or reflectors to the cells underneath. This reduces the efficiency with which the photovoltaic cells may gather light for conversion to electricity. While certain piezo devices have been proposed for cleaning photovoltaic panels, those devices are implemented only as a supplementation for a cleaning system that primarily utilizes electrostatic fields.
Some prior attempts at solving dust settling problems have used passive structures built onto photovoltaic panels in an attempt to create air currents over the surface of the photovoltaic panels. While these structures may remove some dust from the surface of photovoltaic panels, they require natural airflow (i.e., wind) over the panels and do not provide for fine-tuning if the wind is inadequate for removing dust particles. Thus, needs exist for improved self-cleaning photovoltaic panels or cells.